intro story D-Flow FM


D-Flow Flexible Mesh

D-Flow Flexible Mesh (D-Flow FM) is the new software engine for hydrodynamical simulations on unstructured grids in 1D-2D-3D. Together with the familiar curvilinear meshes from Delft3D 4, the unstructured grid can consist of triangles, pentagons (etc.) and 1D channel networks, all in one single mesh. It combines proven technology from the hydrodynamic engines of Delft3D 4 and SOBEK 2 and adds flexible administration, resulting in:

  • Easier 1D-2D-3D model coupling, intuitive setup of boundary conditions and meteorological forcings (amongst others).
  • More flexible 2D gridding in delta regions, river junctions, harbours, intertidal flats and more.
  • High performance by smart use of multicore architectures, and grid computing clusters.
An overview of the current developments can be found here.
The D-Flow FM - team would be delighted if you would participate in discussions on the generation of meshes, the specification of boundary conditions, the running of computations, and all kinds of other relevant topics. Feel free to share your smart questions and/or brilliant solutions! 


We have launched a new website (still under construction so expect continuous improvements) and a new forum dedicated to Delft3D Flexible Mesh.

Please follow this link to the new forum: 

Post your questions, issues, suggestions, difficulties related to our Delft3D Flexible Mesh Suite on the new forum.





Sub groups
D-Flow Flexible Mesh
Cohesive sediments & muddy systems


Message Boards


Nicolas Giussano, modified 7 Years ago.


Youngling Posts: 2 Join Date: 7/17/13 Recent Posts

When I use Manning formula for bottom roughness, using a Manning number under 0,1 I find this error "child process exited abnormally".
How can I solve this problem? I´m working on a damn and I should use a Manning number about 0,02.

Adri Mourits, modified 7 Years ago.

RE: MANNING (Answer)

Yoda Posts: 1221 Join Date: 1/3/11 Recent Posts
Hi Nicolas,

0.02 is a typical Manning value. I don't think this causes your problem.

The error "child process exited abnormally" can have a lot of causes. Does the generated tri-diag file contain information about what goes wrong?
If the error appears during the calculation, have a look at the map-fields just before the crash. That might help to detect where (and why) it starts to go wrong.